Question

When gas C is mixed with gas B, dense white fumes are seen and there is no other product. What is the name of the product of the reaction between gas B and gas C?
[Note: gas B turns moist red litmus paper blue]
(A) Ammonium Chloride
(B) Hydrogen
(C) Nitrogen
(D) None of these

Answer 1

litmus test is the test that is used to decide whether a given sample is acidic or basic. The sample of the compound is applied to the moist litmus paper. The paper turns blue in case the sample is basic and the sample that turns the litmus paper red is the acidic sample. The litmus paper must be dampened before the application of the sample on the paper.

Complete step by step answer:
The question gives the reaction in which two reactants react and form the product which exists in the gaseous phase.
The gaseous product has a distinct property of existing in the form of white fumes. It is also given that the gas B turns moist litmus paper to blue thus indicating the basic nature of the product. This means B is basic.
Hydrogen gas is a colorless, odorless, tasteless, non-toxic, non-metallic gas that can’t be the product since it is not white nor it is basic.
The gas can’t be nitrogen either as nitrogen is a corrosive brown gas rather than white which is the color of the product. It is not nitrogen.
The option ammonium chloride is both existent as white fume and can be formed with the reaction of a basic reactant with an acidic one. So, it can be concluded that the fume product is ammonium chloride

So, the correct answer is Option A .

Note: When acid and bases react they form a product which is a salt of the two reactants. This salt is mostly neutral and thus shows a neutral effect on the litmus paper as well, that is, the litmus paper is usually unaffected by its application. The sample which is to be tested with the litmus paper should be applied to a damp litmus paper for it to be properly analyzed.